fix(chromium): waitForSelector and waitForExpression poll indefinitely when the main page returns a bad HTTP status (e.g., 500)

pkg/modules/chromium/browser.go

@@ -382,6 +382,7 @@ func (b *chromiumBrowser) do(ctx context.Context, logger *slog.Logger, url strin
 			ignoreResourceHttpStatusDomains: options.IgnoreResourceHttpStatusDomains,
 			invalidResourceHttpStatusCode:   &invalidResourceHttpStatusCode,
 			invalidResourceHttpStatusCodeMu: &invalidResourceHttpStatusCodeMu,
+			cancelOnMainPageError:           taskCancel,
 		})
 	}
 
@@ -411,11 +412,45 @@ func (b *chromiumBrowser) do(ctx context.Context, logger *slog.Logger, url strin
 		loadingFailedMu:         &loadingFailedMu,
 		resourceLoadingFailed:   &resourceLoadingFailed,
 		resourceLoadingFailedMu: &resourceLoadingFailedMu,
+		cancelOnMainPageError:   taskCancel,
 	})
 
-	err = chromedp.Run(taskCtx, tasks...)
-	if err != nil {
-		errMessage := err.Error()
+	runErr := chromedp.Run(taskCtx, tasks...)
+
+	// Check event-driven errors first — they take priority over chromedp.Run
+	// errors because they carry the actual root cause (e.g., HTTP 500 from
+	// the main page). When we cancel taskCtx on a main page error,
+	// chromedp.Run returns a context error that is less informative.
+	// See https://github.com/gotenberg/gotenberg/issues/1492.
+
+	// See https://github.com/gotenberg/gotenberg/issues/613.
+	invalidHttpStatusCodeMu.RLock()
+	defer invalidHttpStatusCodeMu.RUnlock()
+
+	if invalidHttpStatusCode != nil {
+		return fmt.Errorf("%v: %w", invalidHttpStatusCode, ErrInvalidHttpStatusCode)
+	}
+
+	// See https://github.com/gotenberg/gotenberg/issues/1021.
+	invalidResourceHttpStatusCodeMu.RLock()
+	defer invalidResourceHttpStatusCodeMu.RUnlock()
+
+	if invalidResourceHttpStatusCode != nil {
+		return fmt.Errorf("%v: %w", invalidResourceHttpStatusCode, ErrInvalidResourceHttpStatusCode)
+	}
+
+	// See:
+	// https://github.com/gotenberg/gotenberg/issues/913.
+	// https://github.com/gotenberg/gotenberg/issues/959.
+	loadingFailedMu.RLock()
+	defer loadingFailedMu.RUnlock()
+
+	if loadingFailed != nil {
+		return fmt.Errorf("%v: %w", loadingFailed, ErrLoadingFailed)
+	}
+
+	if runErr != nil {
+		errMessage := runErr.Error()
 
 		if strings.Contains(errMessage, "Printing failed (-32000)") {
 			return ErrPrintingFailed
@@ -437,23 +472,7 @@ func (b *chromiumBrowser) do(ctx context.Context, logger *slog.Logger, url strin
 			return ErrRpccMessageTooLarge
 		}
 
-		return fmt.Errorf("handle tasks: %w", err)
-	}
-
-	// See https://github.com/gotenberg/gotenberg/issues/613.
-	invalidHttpStatusCodeMu.RLock()
-	defer invalidHttpStatusCodeMu.RUnlock()
-
-	if invalidHttpStatusCode != nil {
-		return fmt.Errorf("%v: %w", invalidHttpStatusCode, ErrInvalidHttpStatusCode)
-	}
-
-	// See https://github.com/gotenberg/gotenberg/issues/1021.
-	invalidResourceHttpStatusCodeMu.RLock()
-	defer invalidResourceHttpStatusCodeMu.RUnlock()
-
-	if invalidResourceHttpStatusCode != nil {
-		return fmt.Errorf("%v: %w", invalidResourceHttpStatusCode, ErrInvalidResourceHttpStatusCode)
+		return fmt.Errorf("handle tasks: %w", runErr)
 	}
 
 	// See https://github.com/gotenberg/gotenberg/issues/262.
@@ -464,16 +483,6 @@ func (b *chromiumBrowser) do(ctx context.Context, logger *slog.Logger, url strin
 		return fmt.Errorf("%v: %w", consoleExceptions, ErrConsoleExceptions)
 	}
 
-	// See:
-	// https://github.com/gotenberg/gotenberg/issues/913.
-	// https://github.com/gotenberg/gotenberg/issues/959.
-	loadingFailedMu.RLock()
-	defer loadingFailedMu.RUnlock()
-
-	if loadingFailed != nil {
-		return fmt.Errorf("%v: %w", loadingFailed, ErrLoadingFailed)
-	}
-
 	// See https://github.com/gotenberg/gotenberg/issues/1021.
 	if options.FailOnResourceLoadingFailed {
 		if resourceLoadingFailed != nil {

pkg/modules/chromium/events.go

@@ -168,6 +168,7 @@ type eventResponseReceivedOptions struct {
 	ignoreResourceHttpStatusDomains []string
 	invalidResourceHttpStatusCode   *error
 	invalidResourceHttpStatusCodeMu *sync.RWMutex
+	cancelOnMainPageError           context.CancelFunc
 }
 
 // listenForEventResponseReceived listens for an invalid HTTP status code
@@ -206,6 +207,14 @@ func listenForEventResponseReceived(
 					defer options.invalidHttpStatusCodeMu.Unlock()
 
 					*options.invalidHttpStatusCode = fmt.Errorf("%d: %s", ev.Response.Status, ev.Response.StatusText)
+
+					// Cancel the task context so that any in-flight wait
+					// operations (waitForSelector, waitForExpression, etc.)
+					// abort immediately instead of polling until timeout.
+					// See https://github.com/gotenberg/gotenberg/issues/1492.
+					if options.cancelOnMainPageError != nil {
+						options.cancelOnMainPageError()
+					}
 				}
 
 				return
@@ -309,6 +318,7 @@ type eventLoadingFailedOptions struct {
 	loadingFailedMu         *sync.RWMutex
 	resourceLoadingFailed   *error
 	resourceLoadingFailedMu *sync.RWMutex
+	cancelOnMainPageError   context.CancelFunc
 }
 
 // listenForEventLoadingFailed listens for an event indicating that the main
@@ -353,6 +363,13 @@ func listenForEventLoadingFailed(ctx context.Context, logger *slog.Logger, optio
 
 				*options.loadingFailed = fmt.Errorf("%s", ev.ErrorText)
 
+				// Cancel the task context so that any in-flight wait
+				// operations abort immediately.
+				// See https://github.com/gotenberg/gotenberg/issues/1492.
+				if options.cancelOnMainPageError != nil {
+					options.cancelOnMainPageError()
+				}
+
 				return
 			}